The present invention is directed to a device for double encasing a rope-like material containing one or more light waveguides which have been stranded together. The device utilizes two extruders which are spaced to extrude a first layer onto the rope-like material and then subsequently extrude a second layer onto the first layer.
It is known that two sheathing layers can be successively applied by extruders when cladding rope-like material containing one or more light waveguides. An example is disclosed in U.S. Pat. No. 4,414,165 which was based on the German application No. 31 11 963. As disclosed in this U.S. Pat. No. 4,414,165, whose disclosure is incorporated by reference thereto, a filling compound which provides a cooling effect and thereby shortens the stretching cone for the extrusion nozzles is applied before the application of the inside or inner sheath or cladding. In many cases however, it is desirable to increase the working speed, for example, the rate of passage of the bundle of optical fibers to such a degree that an adequate solidification can no longer be achieved by using such cooling measures in the brief time available unless unnecessarily great distances are provided between the first and second extruder. However, increasing the distance between the first and second extruder has proven extremely unfavorable because of the great space requirement among other things and moreover due to the over-stressing of the mechanical stability of the yet-unhardened cladding layers or sheaths.